In this Dec. 20 file photo, Chris Serrano (left) and Clifton Webb embrace after being married, as people wait in line to get licenses outside of the marriage division of the Salt Lake County Clerk’s Office in Salt Lake City, Utah. (AP-Yonhap News)

Utah had filed an emergency request to stay the judge’s ruling, which struck down as unconstitutional a state law banning same-sex marriage.

In a brief decision, liberal justice Sonia Sotomayor granted the request by Utah’s attorney general Sean Reyes “pending final disposition of the appeal by the United States Court of Appeals for the Tenth District.”

In his Dec. 20 ruling, federal district judge Robert Shelby said the Utah ban ― approved by voters in a referendum in 2004 ― violated the right of same-sex couples to equal protection under the law.

Besides temporarily shutting down same-sex marriages in Utah, the ruling was important because it put in question gay marriage bans adopted by 30 U.S. states.

Seventeen U.S. states and the federal capital Washington, D.C., have so far legalized same-sex marriage.

Since Shelby’s ruling, hundreds of same-sex couples have married in Utah, a conservative state with a large Mormon population.

It is unclear what would happen to those marriages if the federal appeals court in Denver, Colorado upholds the state’s ban on gay marriages.

In the United States, it falls to states to make the laws governing marriage.

In Utah‘s request for a stay of Shelby’s ruling, governor Gary Herbert cited a Supreme Court decision at the end of June in the case of “Windsor v. United States” that reaffirmed that principle.

In that decision, the Supreme Court struck down a federal law that refused marriage benefits to legally married homosexuals. But it recalled that marriage was a matter for the states.

“The district court’s due process analysis is contradicted, not supported, by Windsor,” he contended.

Sotomayor, who is in charge of emergency requests for a region that includes Utah, also recently granted a request by a religious organization to stay a provision in President Barack Obama’s signature health care reform law requiring coverage of birth control methods.